Method of forming coils for electric apparatus.



L. W. CHUBB.

METHOD 0F FOBMING GOILS POR ELECTRIC APPARATUS.

APPLIQATIOI FILED .TUBE 25, 1907.

Patented Aug. 8, 1911.

INVENTOR wnNfssEs f lUNITED sTATEs 'PATENT oiuucii.

LEWIS WQCHUBB, OF WILKINSBUBG, PENNSYLVANIA, ASSIGNOBATO WESTINGIIOUSE l ELECTRIC &.MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

1 be readily i METHOD OF FORMING COILS FOR ELECTRIC AIPARATUS.

Specication of Letters Patent. Patented Aug. 8, 1911;

.` Application led June 25, 1907. Serial N0. 380,710.

To all whom 'it may concern:

Be it known. that I, LEWIS W. CHUBB, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement inMethods of Forming Coils for Electric Apparatus, of which the follbwing is a specification. My invention relates `to coils for electric apparatus and it' has for its object to provide an improved methii of forming and insulating edgewise-wound strap coils which are adapted for use in are lamps, circuit breakersfthe field magnet windings of dynamo-electric' machines and various other relations. l v.

' In co-.pending applications, Ifiled of even date, herewith and entitled respectively, Processes for coating electric conductors and Systems for coatingwires and cables, I have described continuous processes 'of producing very -hard insulating films on the surfaces of aluminum wires and other conductors. These processes are particularly adapted to relatively small wires which may wound into coils without injuring their insulating coatings'. Accordingr to -my present invention, I pro- V'vide .a simplefa'nd-eective method of formavo ing and coating coils, such as those `which A'are o ften used in the field magnet windings ofdynamo-electric machines, having a number of turns of edgewise-wound strap conductor,with avery thin insulating oxid film.

In the accompanying drawings,v4 Figure 1 is-a diagrammatic view of .a coil undergoing theprocess of coating andy the apparatus I utilized in practicing the 'process and Figs.

and 3 are perspective viewsof different frrns' of completed coils.

4Referring to the drawings, a suitable lengthof strap or a ba-r of aluminum o r other conducting material isfirst bent into the form of an open helix. This bending process may be accomplished in any .well

' known manner and the coil, in, this condition,'is next immersed in a bathof sodium silicate solution, ammonium borate solution' or other suitable liquid lwhich is 4capable of producing anelectmlyt-ic valve action. An electric cu'rent is then passed throught-he bath and throu h thehelix, as one'of the electrodes, there y producing-an insulating film on the surface of the latter Vthat is capable of resisting the voltage strains which exist between the adjacent turns of the coil when it is completed.

An electric current may be supplied to the open helix 1 from a generatorQ, or other suitable source, through a conductor 3', the circuit being completed from lthe helix) through4 the bath Iiin which the coil issubmerged, a metallic lining 5 of4 a tank or vessel 6 in which the bath is contained and a conductor 7 which is connected to the opposite terminal of the generator 2. A similar result may be eifected-by immersing two coils in a single bath and connecting them to opposite terminals of an alternating current source.

After the helix is finally treated electrolytically as above indicatedits adjacent convoltions are forced into .close proximity to,y

each other.

It is conceivable that various modificar" tions in the apparatus and method of practicing my invention may be effected without departing from the spiritof my invention.

I claim as my invention: j

l. The method of constructing a coil for electric apparatus which consists in bending .a conductor into an open helix, immers ing the same in a bath of sodium silicate solution capable of producing an electrolytic valve action, passing an electric currentrthrough the helix as one electrode and through the bath to the other electrode, and

finally forcing adjacent convolutions of the .Y

helix into close proximity.

2. The' methodbf constructing an edgewise-wound aluminum strap' coil for electric apparatus which consists in bending a strap conductor into an open helix, immersing the same in a bath of sodium silicate, passing an electric current through the helix i as one lelectrode and through the bath to theother electrode, and finally pressing the adjacent convolutions of the helix into close prox-` imity to each other.'

In testimonyj whereof, I have hereunto subscribed my name this 20th day of June,-

' LEWIS W. CHUBB. Witnesses:

R. D. DE WoLr,

BIRNEY HINEs. 

